This invention relates to an inorganic fiber-reinforced metallic composite material (to be abbreviated as a composite material) having excellent mechanical properties and comprising a matrix of a metal or its alloy (to be inclusively referred to as a metal) and inorganic fibers composed mainly of silicon, either titanium or zirconium, carbon and oxygen as a reinforcing material.
Some patent documents including Japanese Laid-Open Patent Publications Nos. 7811/1977, 24111/1977, 30407/1978 and 26305/1977 disclose that non-surface-treated silicon carbide fibers obtained by spinning organic silicon polymers called polycarbosilanes, rendering the fibers infusible and calcining the infusible fibers show excellent mechanical strength when used as reinforcing fibers for metals such as aluminum, magnesium and titanium. However, when these silicon carbide fibers are immersed in a molten bath of a metal such as aluminum, their strength is reduced markedly as shown in Referential Example given hereinafter, and the strength of a composite material composed of a matrix of aluminum and the reinforcing silicon carbide fibers is much lower than its theoretical strength calculated from the strength and volumetric proportion of the fibers.